Abstract
A review of the literature discussing the relationship between mechanical factors and osteoarthrosis (OA) is given. From this review, it is concluded that the impulsive loads experienced at heelstrike during normal level walking are associated with degeneration of the joints of the lower limb. The amount of loading experienced varies between individuals and it is proposed those with higher loading have a greater risk of developing OA. The apparatus and methods used to study the differences in heelstrike impulsive loading (HIL) in a subject population are described.
The data from the gait studies is analysed using kinematic and kinetic models. The data confirms that the subject population consisted of two groups, one with a large HIL, the other with a small HIL. These differences are attributed to the kinematics of the swing leg, in particular the vertical velocity of the ankle at heelstrike.
A two dimensional simulation model of the swing phase is developed. This model is used, together with an numerical technique, to change the swing phase pattern of a subject with a large HIL to that typical of a subject with a small HIL. The differences in joint moment between these two patterns is evaluated.
A sagittal plane model of the patellofemoral joint is developed and described. This model is incorporated into an existing mathematical model of the lower limb. The lower limb model is used to evaluate the differences in muscular control effort required for the two swing phases described above. Differences are found in the phasing of the hip flexor muscles.
It is concluded that changes in muscular phasic activity during early swing phase, combined with the dynamics of the swing leg, produce significant changes in the approach velocity of the ankle at heelstrike. Thus, the loading experienced at heelstrike is a function of the timing of muscle activity during swing phase and can be altered by training, so that preventative treatment of OA is possible.
The data from the gait studies is analysed using kinematic and kinetic models. The data confirms that the subject population consisted of two groups, one with a large HIL, the other with a small HIL. These differences are attributed to the kinematics of the swing leg, in particular the vertical velocity of the ankle at heelstrike.
A two dimensional simulation model of the swing phase is developed. This model is used, together with an numerical technique, to change the swing phase pattern of a subject with a large HIL to that typical of a subject with a small HIL. The differences in joint moment between these two patterns is evaluated.
A sagittal plane model of the patellofemoral joint is developed and described. This model is incorporated into an existing mathematical model of the lower limb. The lower limb model is used to evaluate the differences in muscular control effort required for the two swing phases described above. Differences are found in the phasing of the hip flexor muscles.
It is concluded that changes in muscular phasic activity during early swing phase, combined with the dynamics of the swing leg, produce significant changes in the approach velocity of the ankle at heelstrike. Thus, the loading experienced at heelstrike is a function of the timing of muscle activity during swing phase and can be altered by training, so that preventative treatment of OA is possible.
Original language | English |
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Qualification | Ph.D. |
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Award date | 1 Aug 1996 |
Publication status | Published - 1996 |